1. Field of the Invention
The invention relates to gas fuel leak prevention in a gas supply apparatus.
2. Description of the Related Art
Fuel cells have recently gained attention as driving sources for vehicles. A fuel cell is an apparatus that generates electricity by means of an electrochemical reaction between hydrogen and oxygen. The hydrogen, which serves as fuel gas, is supplied to the fuel cell from a hydrogen gas tank, where it is stored under high pressure. A valve that controls the flow of the hydrogen gas is arranged between the hydrogen gas tank and a gas line that supplies the gas to the fuel cell. One such valve has an electromagnetically controlled solenoid valve mechanism so that when it is energized the valve opens, and when it is de-energized the valve closes.
Technology disclosed in JP(A) 7-301359 prevents hydrogen gas from leaking by making the structure of the solenoid valve mechanism one in which a valve closes in the event of electrical failure or damage to the valve body due to the fact that the valve is set to be closed during normal operation.
With this technology, however, if a gas line connected to the hydrogen gas tank is damaged by impact during a vehicle collision, for example, there is a possibility that the solenoid valve mechanism may be energized and the valve may open, resulting in a fuel gas leak unless, the solenoid valve mechanism fails electrically or is also damaged.
This kind of problem is not limited to fuel cell systems, but also appears in various gas storage containers. In view of the foregoing problem, it is an object of this invention is to prevent a gas leak using a simple structure.